[gtksourceview] .gitlab-ci.yml: set default C/C++ std for fedora build

[Christian Hergert <chergert src gnome org>]

commit 2734c4bd42d24f3168439f1607e504b395b295f9
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 6 16:25:50 2022 -0700

    .gitlab-ci.yml: set default C/C++ std for fedora build
    
    We might have to compile libsass, which will want a newer cpp_std.

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index c3d1f925..b52b5976 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -24,7 +24,7 @@ reference:
     stage: docs
     needs: []
     variables:
-        MESON_FLAGS: "-Dwerror=true --buildtype=release -Dgtk:media-gstreamer=disabled 
-Dgtk:broadway-backend=false -Dgtk:demos=false -Dgtk:build-examples=false -Dgtk:build-tests=false 
-Dgtk:werror=false -Dlibsass:werror=false -Dsassc:werror=false -Dlibadwaita:werror=false"
+        MESON_FLAGS: "-Dc_std=c11 -Dcpp_std=c++11 -Dwerror=true --buildtype=release 
-Dgtk:media-gstreamer=disabled -Dgtk:broadway-backend=false -Dgtk:demos=false -Dgtk:build-examples=false 
-Dgtk:build-tests=false -Dgtk:werror=false -Dlibsass:werror=false -Dsassc:werror=false 
-Dlibadwaita:werror=false"
     script:
         - sudo dnf -y install git libpng-devel libjpeg-turbo-devel expat-devel
         - mkdir -p pfx/